It is well know that fluid inclusion is a kind of sample reserved in geological body during the formation of rocks, minerals, deposits and so on. The fluid inclusion can provide various kinds of information, such as the formation conditions of rocks and minerals, and the storage, migration and evolution of oil and natural gas and the like.
Oil-bearing fluid inclusions generally exist in the samples of sedimentary rocks. Once the oil/gas components in the fluid inclusion are entrapped, they will be reserved in a relatively closed space, and thus can be prevented from alteration effects at later stages, such as biodegradation, water washing and the like. Therefore, the hydrocarbon components in the oil-bearing fluid inclusions can provide the information of original oil/gas composition when captured. The analysis results of oil-bearing fluid inclusions can be directly used in the study on oil source correlation, hydrocarbon migration and the like.
However, fluid inclusions are generally extremely small, and in particular the oil-bearing fluid inclusions have a diameter generally not greater than 20μm. As a result, the techniques for analyzing the composition of fluid inclusion are very challenging, and the sample chamber is crucial in the process of analyzing fluid inclusion by laser ablation.
CN201010521367 discloses a device for isotope analysis of micro-minerals by laser ablation. As shown in FIG. 1, the device includes a sample chamber 300 for laser ablation, and the sample of fluid inclusion can be observed with a microscope via reflected light and thus be analyzed by laser ablation. As shown, the sample chamber 300 comprises a chamber body 307, within which a sample cell is arranged. The sample chamber 300 further comprises a quartz glass plate 303, which is fixed on the upper end of the chamber body 307 through a cover plate 305 and screws 302. For preventing leakage, an O-ring 304 can be further arranged between the quartz glass plate 303 and the chamber body 307. A horizontal gas carrying channel 308 penetrating through two opposite sides of the chamber body is formed inside the chamber body 307, and both ends of the gas carrying channel 308 are connected to outer pipelines with ferrule joints 301 and 306 respectively. In this manner, the carrier gas can pass through the gas carrying channel 308 and sweep the sample in sample chamber. The substances generated enter into a detector through the outer pipelines connected with the joint 306, and then can be analyzed by the detector.
However, the sample chamber 300 still has some defects. For example, the sample chamber cannot be observed through transmitted light, which is crucial for the observation of fluid inclusions. In addition, the sample chamber cannot be heated up in a short time, which enables the whole analyzing process relatively long. Also, the whole sample chamber has to be replaced in case of a breakdown, which needs to shut down the whole device during replacement, thus causing an inconvenient operation.